enlarging a hole

[marinelife]

What is the best way to enlarge a hole for a bulkhead? right now I have a 1.5" bulkhead in my sump and need to go up to a 2" for a new return pump. Is this possible to do? it's an acrylic sump.

 

[homer1475]

While I've never drilled acrylic, I have drilled glass. That 1/2" would be tough on glass, I don't think it would be any fun on acrylic ether.



I would just use a fitting on the end of the bulkhead to go up a 1/2" in size.

 

[GQuinn]

Use a hole saw with a pilot drill in the center. From the back side of the hole clamp a wood block across the center of the existing hole. Make sure the pilot drill sticks out enough that it engages the wood before the hole saw engages the acrylic. The pilot drill will guide the hole saw thru the acrylic.

 

[mcgyvr]

Use a hole saw with a pilot drill in the center. From the back side of the hole clamp a wood block across the center of the existing hole. Make sure the pilot drill sticks out enough that it engages the wood before the hole saw engages the acrylic. The pilot drill will guide the hole saw thru the acrylic.

This....^^^:thumbsup:
Easy stuff in acrylic..
Not nearly as much fun in glass..

 

[Steve175]

yep. acrylic is very easy to drill. but you will need to add a piece of wood to keep the hole saw in place to drill over the existing hole. IMO it is worth redrilling to increase flow into your new pump. An underfed pump is less efficient and it can be a source of annoying microbubbles.

 

[shaginwagon13]

Use a hole saw with a pilot drill in the center. From the back side of the hole clamp a wood block across the center of the existing hole. Make sure the pilot drill sticks out enough that it engages the wood before the hole saw engages the acrylic. The pilot drill will guide the hole saw thru the acrylic.

This....^^^:thumbsup:
Easy stuff in acrylic..
Not nearly as much fun in glass..

+2

You NEED the pilot drill OR somehow maneuver a drill press to make sure the holesaw doesn't skip around until the hole is started. Use some wood and clamps for the inside to cover the current hole so that the pilot drill has something to bite into.

 

[marinelife]

Thanks, everyone, I will be using the wood idea. I will start once I have the pump next week.

 

[albano]

yep. acrylic is very easy to drill. but you will need to add a piece of wood to keep the hole saw in place to drill over the existing hole.

+1... Done this many times...just need a small piece of 1/4" (or thicker) plywood, use your 2" drill to make a hole in it... Once you secure it over the original hole, you have a guide to keep the bit in place

 

[Timfish]

+1... Done this many times...just need a small piece of 1/4" (or thicker) plywood, use your 2" drill to make a hole in it... Once you secure it over the original hole, you have a guide to keep the bit in place

Using a piece of plywood for a jig to hold the bit in place like this works great on glass too. This technique also has the advantage of not needing to have the new hole centered over the old hole.

 

[mcgyvr]

Using a piece of plywood for a jig to hold the bit in place like this works great on glass too. This technique also has the advantage of not needing to have the new hole centered over the old hole.

yep.. you just put the plywood on the top side but this time its got a hole same size as the diamond bit and use it a a guide to keep the diamond bit from walking..
Works perfect there too..

 

[marinelife]

A friend of mine had this for holding hole saws. I used it and it worked great. A 2" home was the limit it would do.



Sent from my iPhone using Tapatalk

 

[mcgyvr]

yep.. that tool works great too if you have one..

 

[sfdan]

This method requires different tools, but it would be my preferable method and certainly would leave a cleaner cut: A handheld router and a flush trim bit. Cut a 2" hole in scrap wood using your hole saw, then clamp that over the existing hole to use as the template. Run the bearing of the flush trim bit along the template and slowly work your way around to expand the hole.

 

[Timfish]

yep.. you just put the plywood on the top side but this time its got a hole same size as the diamond bit and use it a a guide to keep the diamond bit from walking..
Works perfect there too..

Just like Albano said.